From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: [PATCH net/stable] can bcm: fix tx_setup off-by-one errors Date: Fri, 23 Sep 2011 20:23:47 +0200 Message-ID: <4E7CCEB3.4050408@hartkopp.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Linux Netdev List , stable@kernel.org, Andre Naujoks To: David Miller Return-path: Received: from mo-p00-ob.rzone.de ([81.169.146.160]:49940 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750957Ab1IWS21 (ORCPT ); Fri, 23 Sep 2011 14:28:27 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This patch fixes two off-by-one errors that canceled each other out. Checking for the same condition two times in bcm_tx_timeout_tsklet() reduced the count of frames to be sent by one. This did not show up the first time tx_setup is invoked as an additional frame is sent due to TX_ANNONCE. Invoking a second tx_setup on the same item led to a reduced (by 1) number of sent frames. Reported-by: Andre Naujoks Signed-off-by: Oliver Hartkopp --- diff --git a/net/can/bcm.c b/net/can/bcm.c index d6c8ae5..c9cdb8d 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -365,9 +365,6 @@ static void bcm_tx_timeout_tsklet(unsigned long data) bcm_send_to_user(op, &msg_head, NULL, 0); } - } - - if (op->kt_ival1.tv64 && (op->count > 0)) { /* send (next) frame */ bcm_can_tx(op); @@ -970,8 +967,9 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, /* spec: send can_frame when starting timer */ op->flags |= TX_ANNOUNCE; - if (op->kt_ival1.tv64 && (op->count > 0)) { - /* op->count-- is done in bcm_tx_timeout_handler */ + /* only start timer when having more frames than sent below */ + if (op->kt_ival1.tv64 && (op->count > 1)) { + /* op->count-- is done in bcm_tx_timeout_tsklet */ hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL); } else @@ -979,8 +977,11 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, HRTIMER_MODE_REL); } - if (op->flags & TX_ANNOUNCE) + if (op->flags & TX_ANNOUNCE) { bcm_can_tx(op); + if (op->kt_ival1.tv64 && (op->count > 0)) + op->count--; + } return msg_head->nframes * CFSIZ + MHSIZ; }